1. Field of the Invention
The present invention relates to optical and electrical communication, and more specifically to the incorporation of a photodiode and a light emitting diode (LED) on a single base to provide bi-directional translation capabilities between optical and electrical signals.
2. Description of the Prior Art
Optical communication has become an increasingly important field. With the introduction of fiber optic communication, optical communication based on light is replacing electricity in some systems as a means of communication. However, the optical signals must still be converted to or from electrical signals for use in the system. In these systems, it is desirable that the system be able to transform optical signals into corresponding electrical signals and electrical signals into corresponding optical signals to enable the electrical and optical portions of the system to interface properly.
A principal device used in transforming optical signals into electrical signals is the photodiode. A photodiode is comprised of a reverse biased P-N junction. When a photodiode is illuminated with light, it produces current which varies almost linearly with the light flux. A device that is commonly used to transform electrical signals into optical signals is a light-emitting diode or LED. An LED receives an electrical signal and generates a corresponding optical or light signal that varies with the electrical signal.
The above devices are generally incorporated into systems which include both electrical and optical signals to provide a means for translating between the electrical and optical signals. However, the incorporation of these separate devices into systems unduly increases the size of these systems. Therefore, it is desirable to provide a single apparatus which provides bi-directional translation capabilities between electrical signals and optical signals to enable the electrical and optical portions of a system to be able to interface properly.